A national security staffer who tweeted under a pseudonym and leaked internal information for two years was fired by the White House last week.

The Daily Beast reports that Jofi Joseph, the nonproliferation director of the National Security Council, was the man behind the Twitter handle @natsecwonk, which became famous inside the Beltway in 2011 for criticizing White House policies, insulting Administration officials and leaking internal information.

One of the more famous tweets that ignited buzz in Washington disparaged a close adviser of President Obama’s: “I’m a fan of Obama, but his continuing reliance and dependence upon a vacuous cipher like Valerie Jarrett concerns me.”

Joseph, who previously worked as an adviser at the State Department and as a staffer for the Senate Foreign Relations Committee, told Politico in an email, “It has been a privilege to serve in this Administration and I deeply regret violating the trust and confidence placed in me.”